Automatic stoker



M y 1934. w. H. WHITTY ET AL 5 AUTOMATIC STOKER Filed June 11, 1929 5 Sheets-Sheet 1 1771161111) 15' 14/ AL M '7 May 1, 1934. w. H. WHlTTY El AL AUTOMATIC STOKER 5 Sheets-Sheet 2 Filed June 11, 1929 wwwwwwwwwwflg M a, b y 67 210 7778}! May 1, 1934. w. H. WHlTTY El AL AUTOMATIC STOKER Filed June 11, 1929 5 Sheets-Sheet 3 May 1, 1934. w. H. WHITTY ET AL AUTOMAT IC STOKER Filed June 11, 1929 5 Sheets-Sheet 4 y 1934- w. H. WHITTY ET AL 57,400

AUTOMATIC STOKER Filed June 11, 1929 5 Sheets-Sheet 5 wuilwfi I v yg z uzflvm To 7776 y Patented May 1, 1934 UNITED STATES PATENT OFFICE Mass., assignors to Whitty Manufacturing Company, Inc., Boston, Mass, a corporation of Massachusetts Application June 11, 1929, Serial No. 370,001

2 Claims.

Our present invention relates to stokers, and more particularly to improved automatic stokers.

Our present invention is applicable for use with ordinary heating furnaces or with under-feed vor over-feed furnaces and an important object of our invention is the the provision of means for preventing the emission of obnoxious gases from the furnace through the fuel hopper and into the boiler room and also to reduce the fire hazard from this cause. Further, in our present invention we are enabled to utilize a driving mechanism for the fuel feeding means that is rotatable r movable in one direction only and associate therewith a fuel feeding ram which may give a, forward step-by-step movement through a certain definite stroke and afterwards return to its initial position to again repeat this cycle of operations. Also, in connection with the driving and reciprocating means for the fuel feeding ram, we have associated a mechanism for determining or varying the length of time necessary for each stroke thereof.

Also, and in connection with the fuel feeding ram and with the driving means therefor, we have devised an improved operating circuit for the driving motor whereby once the driving ram has been started on its fuel delivering stroke, such stroke will be completed before the driving means is placed out of action, irrespective of whether or not the controlling manual or automatic regulator for the system moves to such position as to shut off power to the driving motor.

Again, and in connection with the fuel feeding ram we have devised an improved means for timing the reversal of the ram and which will be positively and accurately operated by the ram driving means.

Other objects and novel features of the construction and arrangement of parts comprising our invention will appear as the description of the invention progresses.

In the accompanying drawings, illustrating a preferred embodiment of our invention,

Fig. 1 is a front elevation of our device associated with the heating boiler;

Fig. 2 is a plan view, a part of the boiler being shown in section;

Fig. 3 is a vertical section on the line 33 of Fig. 2;

Fig. 4 is a side elevation, a, portion of the boiler furnace being in section and showing the operating circuit for the ram driving motor being diagrammatically shown;

Fig. 5 is an enlarged sectional side elevation on the line 5-5 of Fig. 1;

Fig. 6 is a detail plan of the clutch mechanism for connecting the fuel driving means in the fuel hopper with the driving motor of the feeding ram;

Fig. 7 is a sectional elevation on the line 7-7 of Fig. 5;

Fig. 8 is a sectional elevation on the line 88 of Fig. 5, and

Fig. 9 is a section on the line 9-9 of Fig. 2.

Referring to the drawings, 10 designates generally a furnace provided with a fire box 11, communicating with the outer air through a door 12 and having arranged therein an under feed grate 13. Beneath the under feed grate and centrally with respect thereto is a fuel trough 14. On one or two sides, according to the Width of the furnace, of the trough 14 is an ash pit 15 partitioned from the central Windbox by vertical panels and communicating with the outer air through doors 16.

Below the grate 13 the front wall of the furnace 10 is provided with an orifice 160, communicating with the trough 14. Secured to the furnace front and in alinement with the passageway in the trough 14 is a cylindrical member 17, such member being provided with a flange 18 at one end such flange being provided with perforations through which pass bolts 19 that screw into threaded holes in the front of the furnace 10. Arranged in the ash pit 15 so as to be operable by the handle 20 is the usual draft device 21. The cylindrical member 17 is provided at the end remote from the flange 18 with a similar flange 22, this flange being also provided with a plurality of perforations for the reception of bolts 23 and by means of which bolts the flange 22 is secured to the rear face of 2. casing 24. In the front and rear walls of the casing 24 and in alinement with the axis of the cylindrical member 17 are bearing members 25 and 26 respectively, such bearings being in alinement with eachother, and rotatably mounted in these bearings is a shaft 27. The shaft 27 extends inwardly of the cylindrical member 17 to any desired distance and has formed on such extending end a thread 28 for a purpose to be hereinafter described. Slidably mounted within the cylindrical member 17 is a piston or ram 29, which piston or ram is hollow, as shown in Fig. 5, and has secured at its outer end a bearing member 30 through which the threads 28 are threaded. Secured to the upper end of the member 30 is a pin 31, such pin extending upwardly through a longitudinal slot 32 formed in the cylindrical member 17, and on the pin 31 is rotatably mounted a sleeve 33, for a purpose to be hereinafter described. Screwed into the inner lower face of the piston or ram 29 is a shaft 34, which shaft extends to the right, as viewed in Figure 4, and has secured to or formed integrally with its forward end a member 135 which acts to force the fuel up the inclined surface of the fuel trough 14.

35 designates a driving motor adapted to be connected to a source of power through the conductors 36 and 37, as will be hereinafter described. The motor 35 is provided with a drive shaft 38, which extends into a casing 39 associated with the casing 24 and on such shaft 38, within the casing 39, is secured a worm 40. This worm 4O meshes with and drives a worm wheel 41 secured to the shaft 42 that is rotatably' mounted in suitable bearings in the casing 39 and in the casing 24, as is clearly shown in Fig. 5. Secured to the inner end of the shaft 42 by nut 43 is an eccentric 44. Within the casing 24 is secured a shaft 45 and rotatably mounted on this shaft 45 is a hub 46 that has secured thereto or formed integrally therewith a downwardly depending lever arm 47, and also a segmental worm wheel 48. To the lower end of the lever arm 47 is pivotally mounted at 49 one end of an eccentric strap 50, as clearly shown in Fig. 7. To the other end of the eccentric strap 50 is pivotally attached, at 51, the lower end of the connecting rod 52. The upper end of the connecting rod 52 is pivotally attached at 53 to spaced plates 54. The p1ates'54 are substantially circular in form and equally spaced about the center of the circular plates are shafts 55 and on such shafts are rotatably mounted pinions 56. The shafts 55 are fixed to said plates 54 and span the space therebetween, as clearly shown in Fig. 5. Keyed to the shaft 27 is a gear 57, such gear being located between the spaced plates 54 and meshing with the pinions 56. Also located between the plates 54 and meshing with the pinions 56 is an internal gear 58, such gear being provided on its outer periphery with a ratchet 59. On the opposed interior walls of the casing 24 are lugs 60, having arranged therein shafts 61 and on which shafts are rotatably mounted pawls 62 adapted to engage with the ratchet 59 in a manner to be hereinafter described. The eifective length of stroke of the right-hand end of the eccentric strap 50, viewing Fig. 7, is determined by the position of the shaft 42 relative to the points 49 and 51 and this dis tance may be varied in the following manner and by the following means: Formed on the inner face of one side of the casing 24 is a bearing member 63 and in such bearing member 63 is rotatably mounted a vertical shaft 64 provided at one end with a worm 65 meshing with the partial worm wheel 48 and at its upper end with a bevelled pinion 66, which bevelled pinion meshes with a corresponding pinion 67 secured to one end of a shaft 68 rotatably mounted in bearings in the casing 24, such shaft extending outwardly through the casing 24 and having attached to its outer end an operating wheel handle 69 by means of which the shaft 68 may be rotated. Rotary movement of the shaft 68, therefore, will cause a corresponding rotary movement of the shaft 64 and thus a rotary movement of the hub 46, thereby swinging the lever arm 47 about the pivot 45 as a center, and moving the shaft 49 either to the right or left, as viewed in Fig. 7 so as to move the center of the pivot 51 away from or toward the center of the shaft 42, thus either lengthening or shortening the effective stroke of the eccentric strap 50.

Secured to the shaft 27 is a pinion 79 which meshes with and drives a gear '71 rotatably mounted on a stub shaft '72 secured to the casing 24. Secured to the gear 71 is a laterally extending shaft '73, on which is rotatably mounted a pinion 74. On an extension of the stub shaft 72 are arranged gears '76 and 77, both of which mesh with the pinion 74 on the shaft 73. The gear '76 is secured to the stub shaft 72 by pin 78. The gear 77 is rotatably mounted on the shaft 75 and such gear '77 has one less tooth than the gear 76. It is obvious, therefore, that as the gear 71 rotates, the pinion '74 will also rotate because of its engagement with the gear 76. The gear 76, however, will remain stationary and the gear 77 will be rotated a distance of one tooth for each full revolution of the gear 71. Rotatably mounted on the shaft 75 is a hub '79, such hub having formed integrally therewith an arm 80 that extends upwardly and carries at its outer end a weight 81. The hub 79 has formed thereon spaced arms 82, either of which is adapted to engage with a pin 83 secured to and extending laterally from the gear '77. Secured in the casing 24 is a shaft 84 and slidably mounted on such shaft is a sleeve 85, such sleeve having thereon spaced collars 86. The inner opposing faces of the collars 86 are adapted to be engaged by the arm 89 and the sleeve to be moved to the right or left, as viewed in Fig. 8, by the weight 81. On each of the pawls 62, 62' and extending laterally therefrom are secured pins 87 and 87' respectively and these pins are adapted ordinarily to engage with the sleeve 85, as clearly shown in Fig. 8, to thereby allow the pawl 62 or 62', with which it is associated, to come into engagement with the ratchet 59 on the internal gear 58, such as shown for example at the right-hand side of Fig. 7, or such pin 8'? is adapted to be engaged by the sleeve 85 to thereby be moved into the position of the left-hand pawl 62 of Fig. 7 g

later when the operation of the entire mechanism L is referred to.

The upper portion of the cylindrical member 1'7 adjacent the flange 18 is flared and open, as indicated at 88, and on such open end is secured, in any convenient manner, a casing 89. Arranged preferably at one side of the furnace 10 is a pedestal 90 having formed integrally therewith and at its upper end an open top casing 91. Extending between the casings 89 and 91 is a cylindrical member 92. Bearings 93 and 94 are formed in the casings 89 and 91 respectively, such bearings being in alinement with each other and in such bearings is rotatably mounted a shaft 95. On the shaft 95 is formed a helical conveying member 96. Secured to the open top of the casing 91 is a fuel hopper 97. Secured to the end of the shaft 95 within the casing 89 is a worm wheel 98 which meshes with and is driven by a worm 99 secured to the shaft 100. The shaft 100 is rotatably mounted in alined bearings 101 and 102 A in the casings 89 and 24 respectively. Secured to the end of the shaft 100 within the casing 24 by set screw 103 is a collar 104. Extending through the shaft 160, adjacent but spaced apart from the collar 104, is a pin 195. Slidably mountratchet clutch member 108, which is associated with the ratchet clutch member 106. Formed integrally with the ratchet clutch member 108 is a sprocket 109, which is in surface alinement with a sprocket 110 secured to the shaft 27 and over the alined sprockets 109 and 110 runs a sprocket chain 111. On the shaft 100 and between the collar 104 and the ratchet clutch member 106 is a compression spring 112 which ordinarily holds the ratchet clutch member 106 in engagement with the ratchet clutch member 108. This construction is such as to cause a positive rotation of the shaft 100 in one direction when the shaft 27 is rotated in a counterclockwise direction and to permit such shaft 100 to remain stationary when the shaft 27 is rotated in a clockwise direction.

Referring now to Fig. 4, 36 and 37 designate the feeding wires leading to a source of power and 35 designates the driving motor for the mechanism just described. This driving motor is connected by conductor 113 with the conductor 37 and by conductor 114 to a terminal 115 of a solenoid switch 116. This solenoid switch is provided with the usual plunger armature that has attached thereto and on opposite sides thereof conducting blades 117 and 118 respectively. The terminal 115 is associated with the blade 117 and also associated with this blade is a terminal 119. The blade 118 has associated therewith the terminals 120 and 121. The terminal 119 is connected by conductor 122 to the conductor 36. Therefore, when the blade 117 is connected to the terminals 115 and 119 an energizing circuit for the motor will be closed from the conductor 36 through conductor 122, terminal 119, blade 117, terminal 115, conductor 114, motor 35, conductor 113 and to the conductor 37. 123 designates a room thermostat connected to conductor 36 by conductor 124 through a controlling switch 125. This room thermostat 123 controls a contact 126 in a conductor 127 leading to one end of the energizing winding of the solenoid switch 116, the other end of this winding being connected by conductor 128 to the conductor 37. In the position shown in Fig. 4, the temperature of the room in which the room thermostat 123 is supposed to be located is relatively high and therefore the solenoid element is out of engagement with the contact 126 and, therefore, the circuit is broken for the energizing winding of the solenoid switch 116. Under these conditions, therefore, if controlled by the thermostat current alone, the blades 117 and 118 would be out of engagement with the various terminals above enumerated and, therefore, no energizing circuit would be closed for the motor 35. Secured to the side of the easing 89 is a switch 129 shown in conventional form as any standard type of limit or makeand-break switch, such switch being connected by conductor 130 to the conductor 36 and by conductor 131 to the terminal 120 of the sole noid switch 116. The terminal 121 of the solenoid switch is connected by conductor. 132 to the conductor 127. The switch 129 is normally closed and, therefore, the conductors 130 and 131 are electrically connected together. If we assume that the blades 117 and 118 are in their low ermost position or out of engagement with the pairs of contacts 115, 119 and 120, 121 respectively, and the temperature of the room in which the room thermostat is located is so low that the element thereof is connected to the contact 126,

-to start the system, therefore, the operator will close the switch 125, thus closing an energizing circuit for the coil of the solenoid switch 116 from conductor 36, conductor 124, switch 125, room thermostat element 123, contact 126, conductor 127, energizing winding of the solenoid switch conductor 128 and to conductor 37. The plunger armature of the solenoid switch will, therefore, be attracted and the blades 117 and 118 will be brought into engagement with the pairs of contacts 115 and 119 and 120, 121 respectively. The energizing circuit above described for the motor 35 is, therefore, closed at the blade 117 and terminals 115 and 119. Also a circuit is closed from conductor 36, conductor 130, switch 129, conductor 131, terminal 120, blade 118, terminal 121, conductor 132, conductor 127, the energizing winding of the solenoid switch 116, conductor 128 and to conductor 37. This last traced circuit, is therefore, a holding circuit for the solenoid switch 116, so that regardless of the fact that when the temperature of the room in which the room thermostat 123 is located becomes high enough to remove the element 123 from the contact 126, the solenoid switch 116 will be retained in operated position.

If We assume that the apparatus has been constructed and arranged as above described, and that the parts are in the position shown in the drawings, and that the operator has closed the switch 125 so as to operate the solenoid switch 116, the motor 35 will be placed in operation, rotating the shaft 38, and through the worm and worm wheel and 41 respectively, will cause a rotation of the shaft 42. The shaft 42 carrying the eccentric 44 will cause an oscillating movement of the eccentric strap about its center of rotation 49 to cause thereby a reciprocating motion of the connecting rod 52 and, therefore, an oscillating movement of the pair of spaced plates 54. As the spaced plates 54referring to Fig. 7-rock in a counterclockwise direction, the gear 57 will remain stationary because of the load on the piston or ram 29. Therefore, the in' ternal gear 58 will rotate in a counterclockwise direction, such direction of rotation being permitted by the pawl 62 that is assumed, at this time, to be in engagement with the ratchet 59 on the internal gear 58. When the spaced plates 54 rock in a clockwise direction or in the direction of the arrow shown in Fig. 7, the internal gear 58 will be held stationary by means of the engagement of the pawl 62 with the ratchet 59, and the pinions 56 engaging with the gear 57 wi l rotate such gear in a clockwise direction or in the direction of the arrow shown in Fig. 7, thus rotating the shaft 27 in a clockwise direction, or in the direction of the arrow shown in Fig. 5. Such shaft rotating, the threads 28 thereon will rotate and the piston or ram 29 will move to the right, as shown in Fig. 5, through a distance determined by the extent of rotary movement of the shaft 27 and the pitch of the threads 28. Also, during this rotary movement of the shaft 27, the sprocket wheel 110 will rotate and through the chain 111 the sprocket wheel 109 will also rotate in a clockwise direction.- Due to the construction of the ratchet clutch members 106 and 108 there wi l be a slipping movement between such members and the shaft 100 will remain stationary. There will thus be no feeding of fuel to the opening 88 during the forward or feeding motion of the piston or ram 29.

The shaft 27 has also secured thereto, as above described, the pinion which meshes with and drives the gear 71 in the direction of the arrow shown in Fig. 8 and the pinion 74 on such shaft 71 engaging with both the gears 76 and 77 and the gear 77 having a different number of teeth than the gear 76 and being loosely mounted on the shaft 75, will rotate on such shaft through a distance equal to one tooth for each revolution of the gear 71. The pin 83 on such gear 77 will, therefore, rotate in a counterclockwise direction, as viewed in Fig. 8, and move the arm 80 carrying the weight 81 through a definite angle. This intermittent rotary movement of the shaft 27 and the shaft 100, as well as the intermittent movement of the pin 83 will continue until the pin 83 has moved in a counterclockwise direction, as viewed in Fig. 8, a sufficient distance to bring the arm 80 slightly past a vertical position, whereupon the weight 81 will swing the arm 80 into its extreme left hand position, as viewed in Fig. 8, and bringing the other arm 82 into engagement with the pin 83 on the gear 77. This movement of the arm 80 is so timed that when the arm 80 moved to its extreme left hand position, the piston ram 29 will have reached the inner limit of its stroke and will have fed the fuel from the opening 88 in the cylindrical member 17 into the fuel trough 14 and the forward and upward movement of the fuel will be assisted by the shaft 34 and member 135 carried on the front end of the ram 29. It will be noted that as the piston or ram 29 moves forwardly or to the right, as shown in Fig. 5, no noxious gases will be backed up through the fuel because of the fact that the fuel is compressed and also that when the piston or ram 29 has reached its innermost limit of travel,

; communication between the fire box and the opening 88 in the cylindrical member 17 is completely shut off. When the arm 80 has been moved into its extreme left hand position, as viewed in Fig. 8, it will, in moving into such position, engage with the left hand collar 86 on the sleeve 85 and such sleeve 85 will be moved to the left, as viewed in Fig. 8, thereby moving the pin 87 at the left of such Fig. 8 upwardly so as to raise the lefthand pawl 62 out of engagement with the ratchet 59 and allowing the right hand pin 87 to drop downwardly that is, referring to Fig. 7, the right hand pawl 62 will be lifted out of engagement with the ratchet 59 and the left hand pawl 62 allowed to come into engagement with such ratchet. Under these circumstances, and assuming the motor 35 to be still rotating in the same direction as formerly, it will be obvious, referring to Fig. 7, that when the spaced plates 54 are rocked in a counterclockwise direction by the upward movement of the connecting rod 52, the pinions 56 will rotate the gear 57 and, therefore, the shaft 27 in a counterclockwise direction, as counterclockwise rotary movement of the internal gear 58 is prevented by the engagement of the left hand pawl 62 with the ratchet 59.

Under these conditions also, and when the spaced plates 54 rock in a clockwise direction, the friction of the plunger piston or ram 29 is sufficient to maintain the gear 57 stationary and the internal gear 58 will rotate in a clockwise direction. It is obvious, therefore, that under these conditions the piston or ram 29 will be moved to its extreme left hand or outer position, as viewed in Fig. 5. Also the direction of rotation of the shaft 27 having been reversed, the direction of rotation of the gear 77 will be reversed and ultimately the pin 83 thereon will move the arm 80 from its left hand position back into the position shown in Fig. 8. The reversal of movement of the shaft 27 Will cause a reversal of the rotary movement of the sprocket 110, and, therefore, the shaft 100 will be started in movement as soon as the piston or ram 29 starts on its retrograde movement. This rotary movement of the shaft 100 will, through the worm 99 and worm wheel 93, rotate the shaft 95 in a clockwise direction, as viewed in Fig. 5, causing the helical conveyor 96 to again start feeding fuel into the opening 88 in the cylindrical member 1'7. The supply of fuel, therefore, for the next forward stroke of the piston or ram 29 is brought into position during the return movement of such piston or ram.

This sequence of operations will take place indefinitely as long as the motor 35 remains in operation. It may happen that the temperature of the room in which the room thermostat is located becomes sufficiently high before the piston or ram 29 has reached its innermost position to have the operating element thereof move out of engagement with the contact 126. If, under these circumstances, the motor 35 has the operating current cut off therefrom the noxious gases would gradually escape through the bed of fuel and into the boiler room. It was to prevent such a contingency happening that the holding circuit, including the switch 129 and conductors 130 and 131, were incorporated in the present device. Therefore, regardless of the fact that the operating element of the room thermostat 123 is separated from the contact 126, the energizing circuit for the solenoid switch 116 is still maintained and, therefore, the operating circuit for the motor 35 is closed at the contacts 115, 119 and blade 117 and will continue to remain closed until the piston or ram 29 has reached the innermost limit of its stroke, at which time, and assuming the operating element of the room thermostat 123 to be still out of engagement with the contact 126, the member 33 carried'by the member on the ram 29 will engage with the arm of the switch 129, thus breaking the connection between the conductors 130 and 131, and, therefore, breaking the energizing circuit for the solenoid switch'l16. Upon breaking of this energizing circuit the plunger armature thereof will allow the blades 117 and 118 to move out of engagement with the contacts 115, 119 and 120, 121 respectively and the motor will come to rest and with the ram 29 in :such a position as to cut off all communication between the fuel bed and the source of fuel. Not only does this prevent the escape of noxious gases into the boiler room but also lessens the danger of fire burning back into the fuel storage compartment.

Having thus described our invention, what we claim as new is:

1. The combination in an underfeed stoker, of a retort, a ram chamber connected thereto and communicating therewith, a ram in said chamber and adapted to be reciprocated therein, a nut mounted in said ram, a screw engaging in said nut to effect movement of said ram, a single source of power for driving the screw in one direction, means interposed between said nut and the driving means for reversing the direction of rotation of said screw, and means to so position the ram upon stoppage of said driving means as to shut off the communication between said chamber and the retort.

2. The combination in an underfeed stoker, of a retort, a ram chamber connected thereto and communicating therewith, a ram in said chamber, a nut mounted in said ram, a shaft, a screw formed on said shaft and engaging in said nut,

means during retraction only of said ram, and means operative on stoppage of said driving means to so position the ram as to shut off communication between said retort and said fuel supply.

WILBUR H. WHITTY. EDWARD C. TAYLOR. 

